media: i2c: max9286: Configure remote I2C speed from device tree

Read the maxim,i2c-clock-frequency DT property that specifies the speed
of the remote I2C bus, and configure the MAX9286 accordingly. The remote
serializers must all have a matching configuration.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 91d4c96..6643b36 100644 (file)
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -144,6 +144,11 @@ struct max9286_format_info {
        u8 datatype;
 };
 
+struct max9286_i2c_speed {
+       u32 rate;
+       u8 mstbt;
+};
+
 struct max9286_source {
        struct v4l2_subdev *sd;
        struct fwnode_handle *fwnode;
@@ -177,6 +182,7 @@ struct max9286_priv {
        /* The initial reverse control channel amplitude. */
        u32 init_rev_chan_mv;
        u32 rev_chan_mv;
+       u8 i2c_mstbt;
 
        bool use_gpio_poc;
        u32 gpio_poc[2];
@@ -254,6 +260,17 @@ static const struct max9286_format_info max9286_formats[] = {
        },
 };
 
+static const struct max9286_i2c_speed max9286_i2c_speeds[] = {
+       { .rate =   8470, .mstbt = MAX9286_I2CMSTBT_8KBPS },
+       { .rate =  28300, .mstbt = MAX9286_I2CMSTBT_28KBPS },
+       { .rate =  84700, .mstbt = MAX9286_I2CMSTBT_84KBPS },
+       { .rate = 105000, .mstbt = MAX9286_I2CMSTBT_105KBPS },
+       { .rate = 173000, .mstbt = MAX9286_I2CMSTBT_173KBPS },
+       { .rate = 339000, .mstbt = MAX9286_I2CMSTBT_339KBPS },
+       { .rate = 533000, .mstbt = MAX9286_I2CMSTBT_533KBPS },
+       { .rate = 837000, .mstbt = MAX9286_I2CMSTBT_837KBPS },
+};
+
 /* -----------------------------------------------------------------------------
  * I2C IO
  */
@@ -374,7 +391,7 @@ error:
 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
 {
        u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
-                   MAX9286_I2CMSTBT_105KBPS;
+                   priv->i2c_mstbt;
 
        if (localack)
                config |= MAX9286_I2CLOCACK;
@@ -1387,6 +1404,8 @@ static int max9286_parse_dt(struct max9286_priv *priv)
        struct device_node *node = NULL;
        unsigned int i2c_mux_mask = 0;
        u32 reverse_channel_microvolt;
+       u32 i2c_clk_freq = 105000;
+       unsigned int i;
 
        /* Balance the of_node_put() performed by of_find_node_by_name(). */
        of_node_get(dev->of_node);
@@ -1477,6 +1496,23 @@ static int max9286_parse_dt(struct max9286_priv *priv)
        }
        of_node_put(node);
 
+       of_property_read_u32(dev->of_node, "maxim,i2c-remote-bus-hz",
+                            &i2c_clk_freq);
+       for (i = 0; i < ARRAY_SIZE(max9286_i2c_speeds); ++i) {
+               const struct max9286_i2c_speed *speed = &max9286_i2c_speeds[i];
+
+               if (speed->rate == i2c_clk_freq) {
+                       priv->i2c_mstbt = speed->mstbt;
+                       break;
+               }
+       }
+
+       if (i == ARRAY_SIZE(max9286_i2c_speeds)) {
+               dev_err(dev, "Invalid %s value %u\n", "maxim,i2c-remote-bus-hz",
+                       i2c_clk_freq);
+               return -EINVAL;
+       }
+
        /*
         * Parse the initial value of the reverse channel amplitude from
         * the firmware interface and convert it to millivolts.
@@ -1550,10 +1586,16 @@ static int max9286_probe(struct i2c_client *client)
        /* GPIO values default to high */
        priv->gpio_state = BIT(0) | BIT(1);
 
+       ret = max9286_parse_dt(priv);
+       if (ret)
+               goto err_cleanup_dt;
+
        priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
                                                   GPIOD_OUT_HIGH);
-       if (IS_ERR(priv->gpiod_pwdn))
-               return PTR_ERR(priv->gpiod_pwdn);
+       if (IS_ERR(priv->gpiod_pwdn)) {
+               ret = PTR_ERR(priv->gpiod_pwdn);
+               goto err_cleanup_dt;
+       }
 
        gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
        gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
@@ -1580,10 +1622,6 @@ static int max9286_probe(struct i2c_client *client)
        if (ret)
                goto err_powerdown;
 
-       ret = max9286_parse_dt(priv);
-       if (ret)
-               goto err_cleanup_dt;
-
        if (!priv->use_gpio_poc) {
                ret = max9286_get_poc_supplies(priv);
                if (ret)
@@ -1596,10 +1634,10 @@ static int max9286_probe(struct i2c_client *client)
 
        return 0;
 
-err_cleanup_dt:
-       max9286_cleanup_dt(priv);
 err_powerdown:
        gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
+err_cleanup_dt:
+       max9286_cleanup_dt(priv);
 
        return ret;
 }